CHAPTER 8 Skeletal Systems
LANGUAGE OF SCIENCE
Before reading the chapter, say each of these terms out loud. This will help you
avoid stumbling over them as you read.
appendicular skeleton (ah-pen-DIK-yoo-lar SKEL-eh-ton)
[append- hang upon, -ic- relating to, -ul- little, -ar relating to]
axial skeleton (AK-see-all SKEL-eh-ton)
[axi- axis, -al relating to]
carpal bone (KAR-pul bohn)
[carp- wrist, -al relating to]
cervical vertebra (SER-vi-kal VERteh-bra)
[cervi- neck, -al relating to, vertebra that which turns] pl., vertebrae
clavicle (KLAV-i-kul)
[clavi- key, -cle little]
coxal bone (KOK-sal)
[coxa- hip, -al relating to]
cranium (KRAY-nee-um)
[cranium skull]
cribriform plate (KRIB-ri-form)
[cribri- sieve, -form shape]
ethmoid (ETH-moyd)
[ethmo- sieve, -oid like]
Just as skeletal tissues are organized to form bones, the bones are organized or grouped to form the
skeletal system. The rigid bones lie buried within soft tissues, providing support and shape to the
body. Understanding the relationship of bones to each other and to other body structures provides
a basis for understanding the function of many other organ systems. Coordinated movement, for
example, is possible only because of the way bones are joined in joints and the way muscles are
attached to those bones.
The adult skeleton is composed of 206 named bones. Variations in the total number of bones in the
body occur as a result of certain anomalies, such as extra ribs, or from failure of certain small
bones to fuse in the course of development.
In Chapter 7 the basic types of skeletal tissue, including bone and cartilage, were discussed—
providing the background for study in this chapter of individual bones and their interrelationships
in the skeleton. Chapter 9 explores articulations—that is, how the bones form joints.
DIVISIONS OF THE SKELETON
The human skeleton consists of two main divisions—the axial skeleton and the appendicular
skeleton (Figure 8-1). Eighty bones make up the axial skeleton. This includes 74 bones that form
the upright axis of the body and 6 tiny middle ear bones. The appendicular skeleton consists of
126 bones—more than half again as many as in the axial skeleton. Bones of the appendicular
skeleton form the appendages to the axial skeleton: the shoulder girdles, arms, wrists, and hands
and the hip girdles, legs, ankles, and feet.
One of the first things you should do in studying the skeleton is to familiarize yourself with the
names of the individual bones listed in Table 8-1. Next, look at Table 8-2, which lists some terms
often used to name or describe bone markings—specific features on an individual bone. After this
preparation, begin a step-by-step exploration of the skeletal system by studying the illustrations,
text, and tables that constitute the rest of this chapter. To help you learn to distinguish between the
names of bones and the names of their markings, the bone names are highlighted in a boldface font
and the markings are shown in a normal font throughout this chapter.
A picture is worth a thousand words. The illustrations and tables contained in this chapter were
carefully selected and compiled to assist you in visualizing and organizing the material discussed. If
in addition to your textbook, you have access to individual bones or an articulated skeleton in a
laboratory setting, frequent reference to chapter illustrations and tabular material will prove
immensely helpful in your study efforts.
FIGURE 8-1
Lateral view.
Skeleton. A, Anterior view. B, Posterior view. C,
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(Patton 215-223)
Patton, Kevin T.. Anatomy & Physiology (with Media), 7th Edition. Mosby, 012009.
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